Compensator for sag of rope, etc.



June 6, 1933. J. H. MCQUAIDE 1,912,782

COMPENSATOR FOR SAG OF ROPE, ETC

Filed Oct. 6, 1952 m 1 I I m irgya Patented June 6, 1933,

UNITED STATES PATENT OFFICE JAMES H. MCQUAIDE, OF CHICAGO, ILLINOIS, .ASSIGNOR OF ONE-HALF TO CHARLES H. DODGE, OF CHICAGO, ILLINOIS COMPENSATOR FOR SAG OF ROPE, ETC.

Application filed October 6, 1932. Serial No. 636,528.

When ropes, cables, trolleys, and the like are suspended between masts at considerable distances apart, the amount of sag in the catenary thus formed varies very considerably due to changes in temperature.

It is an object of the present invention to provide a means for compensating for this sag and for the resulting changes in tension in the line, so that the rope or the like will remain in substantially the same posiion and at the same tension for all conditions of temperature.

The invention is fully described in the following specification and shown in the ac- 5 eompanying drawing, in which Figure 1 is a diagrammatic View of a plurality of these devices applied to a well known form of trolley wire suspended from a steel rope;

Fig. 2 is an enlarged view partly in section of heavy duty compensating device used on the upper and intermediate ropes of the system; and

Fig. 3 is a similar View showing a form of device adapted to be used on the trolley wire.

The embodiment illustrated shows the device as adapted to be used on a trolley wire and its suspending ropes such as is now used in certain forms of electric railway systems. Referring to Fig. 1, the upper steel rope or main messenger A carries the load of steel rope or auxiliary messenger B and the trolley wire C, the rope A being carried by masts or the like D set at suitable distances apart. The trolley wire G is suspended from the rope B by means of short suspension members E, and the rope B is suspended from the rope A by means of similar members F. The method of suspending these parts is not shown in detail, for the reason that it is well known and is no part of the present invention.

Very great changes in the amount of sag 4 and of the tension in these ropes and trolley wires occur due to changes in temperature,

and the present invention overcomes this difficulty by inserting in these ropes and trolley members, devices which compensate for the change in length thereof due to changes of temperature. A compensating device G, shown in Fig. 2 which will. hereinafter be described in detail, serves to compensate for such changes in the rope A.

A similar but smaller device G of the same character is insertedin the rope B for the reason that the rope B carries only a small fraction of the load carried by the rope A. The trolley wire C carries a'much smaller load than that of the rope B, and the changes in length of the trolley wire are compensated for by the insertion of the compensator H, which is shown in detail in Fig. 3.

The compensator G is composed essentially of a hollow metal bellows 1O filled with a suitable fluid, such as alcohol, which will not freeze at any temperature to which it is likely to be subjected, and which at the same time possesses a relatively high co-eflicient of expansion. Owing to the corrugated bellows form of metal container which is here shown, relatively great changes in length of this device are permitted corresponding to changes in temperature.

This bellows has flat ends which are adapted to bear in a recessed plate 11. At each end, the plate bears against a cross member 12 which is secured at its two ends to side bars 13 which pass along the side of the bellows and preferably in the center thereof, the members 13 being secured at their opposite ends to a cross bar 1% which has a central opening 15, through which passes the rope A, the end being returned and secured by means of a rope clamp, or the like, not shown. The plate 11 at the opposite end is similarly secured to side bars 13 which in turn are fastened to a cross bar 14: to which the rope A is secured, as previously described.

The side bars 18 and 13 serve as guide bars for the circular hollow metal bellows 10 which has lugs 16 engaging each of these side bars. Thus any tendency of the bellows to buckle is prevented.

This construction G is then inserted as indicated in Fig. 1 in the primary messenger A, or it may be used to replace the usual turn buckles, not shown, which are placed at the end of a line or at intervals therein to serve as take-ups for expansion or contraction due to changes in temperature. If desired, a separate and smaller but similar compensator G may be used in the auxiliary messenger B, as shown in Fig. 1. and also a modified form of compensator H may be used in the trolley, as shown in detail in Fig. 3.

This construction H comprises a hollow metal bellows 17 held within a frame 18 which has arms 19 adapted to be slidably mounted on the auxiliary messenger B. This bellows has a series of lugs 20 which are adapted to slide upon guides 21 and 21 on the frame 18 so as to guide the several sections of the bellows and prevent it from buckling or twisting under the load. The guides 21 are held in place by bolts 21 Each end of the bellows bears against a recessed plate 22 which is carried by a rod 23 which has a snug sliding fit in an end of the frame 18. Each end of the frame is made arcuate at Eat to serve as a curved surface, over which an end of the trolley C is adapted to pass. These two ends of the trolley overlap the trolley at the right.- hand end, passing under the device and being secured. as by brazing. to the left-hand rod 23, the left-hand trolley also passes under the device and lies contiguous to the other trolley, and is secured to the right-hand rod 23, the two lying in a suitable groove or grooves in the bottom.

Thus it will be seen that as the temperature rises the two trolley sections C will expand. At the same time the bellows 17 expands. By properly proportioning the length of the bellows and calculating its expansion for a given contained fluid, the total expansion of the bellows can be made to very nearly approximate the total expansion of a given section of trolley, messenger, or the like.

lVhile I have shown and described but a few embodiments of my invention, it is to be understood that it is capable of many modifications. Changes. therefore, in the construction and arrangement may be made which do not depart from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. A sag compensator for a catenary rope and the like comprising an expansible element having a relatively large expansion for each degree rise in temperature, a member bearing on each end of the element and adapted to be attached to said rope to compensate for changes in length due to tear erature changes therein.

A sag compensator for a catenary rope and the like comprising an expansible element having a relatively large expansion for each degree rise in temperature, a stirrup passing around the element and bearing on aeh end of the element and adapted to be attached to said rope to compensate for changes in length due to temperature changes therein.

3. A sag compensator for a catenary rope and the like comprising a metal bellows having a relatively large expansion for each degree rise in temperature, a member bearing on each end of the element and adapted to be attached to said rope to compensate for changes in length due to temperature changes therein.

4. A sag compensator for a catenary rope and the like comprising a metal bellows having arelatively large expansion for each degree rise in temperature, a stirrup passing around the elementand bearing on each end of the element and adapted to be attached to said rope to compensate for changes in length due to tem 'ierature changes therein.

5. A sag compensator for a catenary rope and the like comprising a hollow metal dia phragm filled with a liquid having a relatively large expansion for each degree rise in temperature, a member bearing on each end of the element and adapted to be attached to said rope to compensate for changes in length due to temperature changes therein.

6. A sag (:Oll'lPQDSdtOl for a catenary rope and the like comprising a hollow metal dia-- phragm filled with a liquid having a relatively large expansion for each degree rise in temperature, a stirrup passing around the element and bearing on each end of the element and adapted to be attached to said rope to compensate for changes in length due to temperature changes therein.

7. A sag compensator for a catenary trolley wire and the like comprising an expansible element located at one side of the. trolley wire, and means operably connecting the opposite ends of said element with said rope to compensate for changes in length due to changes in temperature in the wire.

8. A sag compensator for a catenary trolley wire and the like comprising an expansible elementlocated at one side of the trolley wire, a frame for supporting said element, and means guided in said frame operably connecting the opposite ends of said element with said rope to compensate for changes in length due to changes in temperature in the wire.

9. A sag con'ipensator for a catenary trolley wire and the like comprising an expansible element located at one side of the trolley wire, a frame for supporting said element, and rods guided in said frame operably connecting the opposite ends of said element with said rope to compensate for changes in length due to changes in temperature in the wire.

JAMES H. MUQUAIDE. 

